Tissue-based Gene Expression as Potential Biomarkers for IBD Course.

Inflammatory bowel diseases (IBDs) are highly heterogeneous in disease phenotype, behavior, and response to therapy. Diagnostic and therapeutic decisions in IBD are based primarily on clinical and endoscopic severity and histopathologic analysis of intestinal biopsies. With this approach, however, only a minority of patients experience durable remission. This may be due to substantial heterogeneity in disease pathogenicity that is not accounted for by current classification systems. Patients can present with similar clinical and endoscopic severity and receive similar therapy but show divergent response ranging from mucosal/transmural healing to nonresponse. Using mucosal biopsy samples that are already obtained as part of the clinical practice to support the diagnosis and state-of-the-art high throughput sequencing approaches can detect the widest range in host gene expression in the actual lining of the affected gut. These analyses can better dissect disease heterogeneity and guide potential treatment response. Here we review studies that use gut tissue-based gene expression profiles to predict disease outcome in IBD.